永州广聚萤叶甲和豚草卷蛾的种群动态及对豚草的控制效果

【目的】豚草是一种重要的入侵杂草,严重危害农业生产和人类健康。广聚萤叶甲和豚草卷蛾是豚草的专一性天敌。研究这2种天敌在永州的种群动态及其对豚草的控制效果,可以为永州豚草的防控及这2种天敌的有效利用提供依据。【方法】在湖南省永州市江永县豚草大面积发生区域,人工释放广聚萤叶甲和豚草卷蛾,调查这2种天敌在释放区和扩散区的种群动态和对豚草的防治效果,以及这2种天敌在扩散区的越冬情况。【结果】广聚萤叶甲和豚草卷蛾的扩散能力强。释放1个月后,在释放区,广聚萤叶甲各虫态及豚草卷蛾虫瘿均被发现。整体上,随时间延长,广聚萤叶甲各虫态虫口密度先增后减,而豚草卷蛾虫瘿密度呈逐渐降低趋势。释放2个月后,在距释放区边缘10 km的豚草发生区,发现了广聚萤叶甲和豚草卷蛾,且成功建立了种群并顺利越冬。释放区豚草株高几乎没有增加,且叶片最终被取食精光,几乎全部死亡;扩散区豚草株高略有增加,最终近75%叶片被取食。【结论】广聚萤叶甲和豚草卷蛾可在永州成功建立种群并安全越冬,还能自行扩散,可持续控制野外豚草的发生。     

广聚萤叶甲和豚草卷蛾对江西南昌豚草的联合控制作用

【背景】豚草是一种世界性的重要害草,在江西南昌地区普遍发生。广聚萤叶甲和豚草卷蛾是很有利用前景的豚草天敌,而有关这2种天敌在江西南昌地区田间对豚草的联合控制效果尚不明确。【方法】2009年6月25日分别按广聚萤叶甲0.7头.株-1和豚草卷蛾0.4头.株-1的密度在江西南昌豚草入侵地同时释放2种天敌,并于8月4日～9月13日,每隔10d调查广聚萤叶甲各虫态的数量、豚草卷蛾虫瘿数、豚草的株高和死亡株数。【结果】释放前期广聚萤叶甲和豚草卷蛾种群数量增长较快,但释放70d后,豚草植株死亡率达90.14%,天敌种群数量急剧下降;释放80d后,豚草植株死亡率达到100%。此外,在整个调查期间,天敌释放区豚草株高增长缓慢,均极显著低于对照区。【结论与意义】广聚萤叶甲和豚草卷蛾在江西南昌地区田间对豚草的联合控制效果显著,宜在江西大规模推广应用。     

外来植食性广聚萤叶甲对非靶标植物的潜在影响

为评估以入侵豚草为食的外来广聚萤叶甲（Ophraella communa）对非靶标植物的潜在生态风险,采用选择性试验测定了广聚萤叶甲成虫和幼虫对当地代表性植物的取食选择,观察了幼虫在选出的植物上生长发育的适合度表现。结果表明：在5大类52种测试植物中,广聚萤叶甲成虫和幼虫不同程度地取食向日葵、苍耳、天明精、菊芋（仅成虫）、紫茎泽兰（仅幼虫）和石胡荽（仅幼虫）;野外罩笼非选择性测定发现,初孵幼虫在苍耳和向日葵8个品种上可完成发育,直到成虫产卵,并观察到在菊芋上完成幼虫发育,个别到成虫但未产卵;在这些植物上幼虫存活率明显降低,蛹质量明显减轻,成虫产卵明显减少。本文还分析了广聚萤叶甲对少数本土植物以及经济作物向日葵的潜在生态风险。     

广聚萤叶甲和豚草卷蛾对广西来宾豚草的联合控制作用

【背景】豚草已成功入侵广西来宾,对当地生物多样性、农业生产和居民健康造成了严重影响。广聚萤叶甲和豚草卷蛾均为豚草的重要专一性天敌,在湖南等地已有效抑制了豚草的扩散蔓延。【方法】为考查2种天敌在广西对豚草的联合控制作用,于2009年5月24日在广西来宾豚草入侵地区同时释放广聚萤叶甲和豚草卷蛾(2种天敌释放密度均为1170头.hm-2)。【结果】至2009年8月29日释放区内豚草植株死亡率达98%以上,且天敌迅速向邻近豚草发生区扩散,2种天敌对扩散区豚草的控制率可达50%～60%。【结论与意义】2种天敌对豚草具有显著的控制效果,建议在广西大面积推广应用。     

广聚萤叶甲成虫的繁殖习性和活动规律初步观察

广聚萤叶甲Ophraella communa是豚草Ambrosia artemisiifoliaL.的一种重要专一性天敌昆虫,对豚草抑制作用显著。本文在室内对广聚萤叶甲成虫交配和产卵活动进行观察,结果表明广聚萤叶甲成虫一生多次交配多次产卵,雄虫交配前期为2.7d,明显长于雌虫的0.9d。交配雌虫有产卵前期,然后开始产卵。成虫交配活动主要在8:00-21:00,一般产卵高峰在12:00-16:00,在交配后的前16天,雌虫产卵处在高峰期,随后产卵逐渐减少。本论文为进一步开展广聚萤叶甲繁殖生物学研究和大量繁殖提供基础。     

二化螟人工饲料关键因子的优化及其优化配方的饲养效果

采用5因子4水平正交试验,将作者在以前筛选出的二化螟Chilosuppressalis(Walker)人工饲料的5个关键因子进行了进一步的优化,并得出了二化螟人工饲料的优化配方,其成分如下:稻茎粉18.75g、大豆粉15.00g、麦芽粉15.00g、稻糠粉6.25g、茭白茎粉7.50g、干酪素10.00g、酵母粉18.75g、纤维素7.50g、蔗糖15.00g、葡萄糖7.50g、维生素C7.50g、复合维生素B3.00g、胆固醇0.375g、氯化胆碱0.25g、Beck氏盐2.50g、山梨酸1.35g、琼脂13.49g和自来水809.25g。通过连续3代继代饲养试验,比较了该优化配方和二化螟天然饲料水稻茎的饲养效果。结果表明,在一些关键指标上(如存活率、化蛹率和羽化率等),所优化的二化螟人工饲料配方的饲养效果明显的好于其天然饲料水稻茎的;而在许多其它的指标上(如蛹期、成虫期、产卵量、卵期和孵化率等),该优化配方对二化螟的饲养效果与水稻茎的相当;但该配方饲养的二化螟在第3代时幼虫历期明显的比水稻茎的有所延长。     

用正交试验法优选二化螟人工饲料配方

采用15因子2水平正交试验,优选出1种二化螟Chilo suppressalis(Walker)人工饲料配方,筛选出影响二化螟发育的5个关键因子,分别是稻茎粉、麦芽粉、稻糠粉、酵母粉和蔗糖。其中稻茎粉、麦芽粉、酵母粉和稻糠粉影响二化螟的幼虫成活率,蔗糖和麦芽粉影响二化螟的幼虫历期,稻茎粉影响二化螟的蛹重。     

适合三种鳞翅目昆虫的一种人工饲料配方

【目的】昆虫的人工饲养是昆虫学研究和害虫防治技术研究的重要基础,开发一种适用于多种昆虫的人工饲料将大大减少昆虫饲养的成本,提高工作效率。【方法】本研究以美国白蛾Hyphantria cunea(Drury)为初试昆虫,通过两次正交试验开发出一种适合饲养美国白蛾、斜纹夜蛾Prodenia litura(Fabricius)和舞毒蛾Lymantria dispar(L.)3种多食性昆虫的人工饲料配方。【结果】该配方的成分和比例为:麦胚(12%)、蔗糖(2%)、酪蛋白(4.5%)、琼脂(1.5%)、氯化胆碱(0.05%)、韦氏盐(1.0%)、山梨酸(0.4%)、对羟基苯甲酸(0.25%)、抗坏血酸(0.5%)、范氏维生素B(0.003%)、胆固醇(0.1%)和肌醇(0.035%)。【结论】该配方饲养3种昆虫在幼虫历期、蛹重、成蛹率和羽化率等各项指标均表现优良。本研究的试验方法和配方将会为其他多食性昆虫人工饲料的开发提供借鉴。     

稻纵卷叶螟人工饲料配方的优化研究

应用二次正交旋转组合设计对稻纵卷叶螟Cnaphalocrocis medinalis Guenée人工饲料的配方进行了优化,以化蛹率为目标函数建立了二次回归模型,结果表明稻叶粉、麦胚粉、玉米粉、干酪素、酵母对稻纵卷叶螟幼虫发育与化蛹率影响较大,大豆粉的影响不明显。通过统计寻优获得的优化配方为:每135 g人工饲料中,稻叶粉3 g、麦胚粉8 g、玉米粉4 g、干酪素4 g、酵母粉4 g。在温度27℃,相对湿度80%左右,光照L∶D=16∶8的条件下,使用该优化配方饲养稻纵卷叶螟,25.6%的供试初孵幼虫能完成幼虫发育并化蛹,幼虫期平均26.9 d,蛹重16²2mg。与以前的研究结果比较,化蛹率与蛹重均有显著提高,而幼虫历期略短。     

松突圆蚧天敌红点唇瓢虫人工饲料的初步研究

对松突圆蚧主要天敌红点唇瓢虫人工饲料进行了初步研究。结果表明:以鲜猪肝、酵母粉、Vc粉末和蜂蜜(质量比为100∶10∶1∶20)为主要配方的人工饲料,基本满足红点唇瓢虫成虫的营养需要,前期存活率可达60%,但平均雌虫产卵量较低,仅为21.8粒/头。若混合适量的松突圆蚧进行饲养,则可以较好地延长成虫的寿命和产卵量,饲养75 d存活率仍达50%以上,平均产卵量达87.2粒.头-1,饲养效果较好。     

Rapid cold-hardening response in Ophraella communa LeSage (Coleoptera: Chrysomelidae), a biological control agent of Ambrosia artemisiifolia L.

In China, an unintentionally introduced beetle Ophraella communa shows good control efficiency against invasive common ragweed, Ambrosia artemisiifolia. With the aim of understanding the capacity of O. communa to overcome sub-zero low temperature rapidly, the longevity, survival and fecundity of the beetle adults were studied at conditions of different rapid cold-hardening in the laboratory. The results showed that approximately 20% female or male individuals still survive at ?12°C for 2 h, thus the discriminating temperature for rapid cold-hardening of both female and male beetles is ?12°C. The survival, longevity and fecundity of adult beetles were significantly affected by rapid cold-hardening treatments. Compared to the control, the survival rates of adult beetles experiencing 2 h of rapid cold-hardening at 2, 5 and 8°C prior to exposure to its discriminating temperature (?12°C) were significantly increased. Adult longevity and fecundity were significantly higher after pre-treatment at 2, 5 and 8°C for 2 h than those of the control. Both longest longevity and maximum fecundity of adult beetles were observed at the rapid cold-hardening of 2°C. Our experiment implies that the cold-tolerance ability of O. communa can be rapidly increased after rapid cold-hardening treatments, which reveals an important ecological significance for population establishment and expansion of O. communa in the invaded areas of common ragweed.     

Variation in cold hardiness among geographic populations of the ragweed beetle, Ophraella communa LeSage (Coleoptera: Chrysomelidae), a biological control agent of Ambrosia artemisiifolia L. (Asterales: Asteraceae), in China

The ragweed beetle, Ophraella communa, is a potential biological control agent of common ragweed that appeared in Nanjing City in 2001 and has since dispersed throughout southeast China. We compared the cold hardiness of five different O. communa populations by measuring the supercooling point (SCP), water and glycerol contents of adult beetles. All indices of cold hardiness varied significantly among the sampled populations. Male beetles from the most northerly population (Nanjing) had the lowest water content of any sampled and, although female beetles from Nanchang and Miluo had water content similar to those from Nanjing, they were still lower than those of females from Fuzhou and Wuchang. Beetles from the most southerly population (Fuzhou) had the highest SCP, although Nanchang males were not significantly different from Fuzhou males. Glycerol content yielded resolution of populations as follows: Nanjing > Wuchang = Miluo = Nanchang > Fuzhou, with beetles from Nanjing yielding twice the glycerol content of Fuzhou beetles. These results suggest that overwintering O. communa use freeze avoidance to survive winter cold and that geographically separated populations of O. communa are diverging with respect to their baseline cold hardiness in accordance with the severity of low temperatures experienced during the coldest winter months in each locality. The apparent ability of O. communa to rapidly adapt to different climatic conditions is predicted to facilitate its continued range expansion across mainland China, with consequent benefits in terms of fortuitous biological control of common ragweed.     

豚草和苍耳上广聚萤叶甲的寄主选择和取食量比较

为探究豚草与苍耳上的广聚萤叶甲种群是否存在分化,对来自这两种植物上的叶甲(分别称为"豚草叶甲"和"苍耳叶甲")进行了选择性试验,并测定了其对5种近缘植物的取食量.选择性试验结果表明,两群来源不同的叶甲对豚草和苍耳的选择偏好存在显著差异,表现为豚草叶甲更偏好豚草,而苍耳叶甲相对更偏好苍耳.对广聚萤叶甲成虫取食量的测定结果表明,对不同测试植物的取食量随来源寄主植物不同而存在显著差异,两群叶甲对向日葵的取食量存在显著差异,但对其他植物的取食量均无显著差异.豚草叶甲对豚草的取食量显著大干对其他测试植物的取食,24h平均取食量达51.27 mm2,而对其他4种植物的取食量无显著差异,均低于40 m2;苍耳叶甲取食豚草的量为52.24mm2(24 h),与取食向日葵和三裂叶豚草量无显著差异,但显著大干取食苍耳和菊芋的量,取食后两种植物的量没有显著差异.研究结果说明,苍耳属植物可能是广聚萤叶甲除豚草外的另一潜在寄主植物.     

Review of the biology and ecology of a ragweed leaf beetle,Ophraella communa (Coleoptera: Chrysomelidae), which is a biological control agent of an invasive common ragweed,Ambrosia artemisiifolia (Asterales: Asteraceae)

A ragweed leaf beetle, Ophraella communa (Coleoptera: Chrysomelidae), has been highlighted as a potential biological control agent of Ambrosia artemisiifolia. O. communa and A. artemisiifolia are native in North America and alien species in East Asia and Europe. As an invasive weed, A. artemisiifolia causes severe economic losses as reducing agricultural production as well as producing severe allergenic pollen. As an herbivore insect, O. communa has strong host preference on A. artemisiifolia. All the developmental stages of O. communa can be found on A. artemisiifolia and it attacks a single plant in repeated and extended manners. With few individuals on A. artemisiifolia, O. communa can completely defoliate before pollen production. Therefore, O. communa had been focused as a biological control of this invasive weed, but its introduction was denied because of possible damage on an important crop, Helianthus annuus. O. communa was accidentally introduced in East Asia and Europe in 1990s and 2010s, respectively. Fortunately, O. communa population was well established to suppress A. artemisiifolia in the introduced areas. Following detailed field surveys and host specificity tests of O. communa were conducted and proved a strong potential of O. communa as a biological control agent of A. artemisiifolia. Moreover, O. communa has been investigated in physiological and evolutionary studies. In this study, the potential of O. communa as a biological control agent and a study organism are reviewed.     

Effects of age at mating of both sexes on female longevity and fecundity performance in Ophraella communa LeSage (Coleoptera: Chrysomelidae)

Life-history strategies of animals are governed by fitness-related trait trade-offs. In particular, the age at which either one of the two sexes copulate has been shown to affect insect reproductive output and longevity. This suggests that trade-offs between longevity and reproduction might drive the choice of a mating partner based on their age and ultimately such choices might select for different life-histories. Although several studies indicate that female age at mating dictates subsequent insect longevity, fecundity, and egg hatch rate, it is unclear how male age at copulation affects these life-history traits. In this study, we simultaneously investigated the effects of female and male age on female fecundity, eggs hatch rate, and adult longevity in Ophraella communa LeSage (Coleoptera: Chrysomellidae), the primary biological control agent of the invasive common ragweed, Ambrosia artemisiifolia L. We found that young mature females lived significantly longer when they were mated with older males. Maximum female fecundity and subsequent egg hatch rate occurred when young females mated with 3-day-old males. On the other hand, females lived longer when mating with an older male. These findings are in accordance with the cost-of-reproduction concept.     

Gallerucida bifasciata (Coleoptera: Chrysomelidae), a potential biological control agent for Japanese knotweed (Fallopia japonica)

Host specificity of foreign natural enemies are becoming more and more critical in classical biological control programs, as concerns about potential risk from introduced biocontrol agents have been increasing recently. Understanding the insect's fundamental and ecological host ranges is the first step in determining the potential for introduction of an insect to control invasive plants. Japanese knotweed, Fallopia japonica (Houttuyn) Ronse Decraene (Polygonaceae) is an invasive weed in the United States and Europe. A leaf beetle, Gallerucida bifasciata (Coleoptera: Chrysomelidae) is an important natural enemy attacking this plant in Asia. However, its host range records were ambiguous. This study examined the beetle's host specificity through a set of choice and no-choice tests in the laboratory and field in its native China. Gallerucida bifasciata larvae were able to complete development on seven of 87 plant species in larval development tests, while adults fed and oviposited on 10 plants in no-choice tests. Multiple choice tests showed adults strongly preferred Fallopia japonica, Persicaria perfoliata (L.) H. Gross and Polygonum multiflorum Thunb over all other plants. Open field tests and field surveys further revealed that these three species were in its ecological host range. The results of this study suggest that G. bifasciata is a potential promising agent for control of Japanese knotweed in the United States and Europe, although additional host specificity tests and risk assessment should be completed.     

Effect of short-term high temperature stress on the development and fecundity of Ophraella communa (Coleoptera: Chrysomelidae)

Since insects are ectothermic, they are highly vulnerable to the sudden increase of temperature. Indeed, it has been hypothesized that the survival, development, fecundity, and even population expansion of insects are all affected significantly by extremely high temperature. We studied the effect of short-term high temperature stress on the survival and development of different stages, adult longevity and fecundity of Ophraella communa (Coleoptera: Chrysomelidae), a biological control agent of the invasive plant, the common ragweed, Ambrosia artemisiifolia (Asterales: Asteraceae) in the laboratory. The results showed that egg, larval, pupal and adult survival rates were significantly affected after 2 hour-short-stress at high temperatures (35 to 47°C) when compared to the 28°C control. With the exceptions of the control and 35°C stress, survival rate of females was significantly higher than that of males after short-stress at any high temperature. Short-term high temperature stress also significantly impacted longevity and fecundity of adult beetles. Except for control, female longevity was significantly longer than male's after short-stress at any high temperature. The survival rates of different stages, and adult longevity and fecundity of the beetle decreased significantly with the increase of short-term stress temperature. Based on the results of the present study, we conclude that the development and population expansion of O. communa may be significantly affected when they are exposed to a high temperature stage in a summer day in the areas invaded by common ragweed, in southern China.     

Control efficiency of leaf beetle,Ophraella communa,on the invasive common ragweed,Ambrosia artemisiifolia,at different growing stages

Ophraella communa LeSage (Coleoptera: Chrysomelidae), an effective biological control agent of A. artemisiifolia, was unintentionally introduced into China. To understand the biological control potential of O. communa on A. artemisiifolia, plant height, the number of branches and leaf control index of A. artemisiifolia injured by the beetle were determined. The results showed that plant height and number of branches decreased and leaf control index increased with the increasing initial release density of O. communa adults, when they were released at 90–100-cm plant height stage in 2008 and 60–70-cm stage in 2009. Even when O. communa was released at a low average density of 1.07 adults per plant at early growth stage of A. artemisiifolia in 2009, it could significantly suppress plant height and number of branches and led to a higher leaf control index compared with the herbicide treatment with Roundup. Prior to the fructicative period, the leaf control index of A. artemisiifolia by O. communa was up to 1.0 on the 47th day after the average initial release of 12 beetles per plant in 2008 or on the 85th day after the average release of 1.07 beetles per plant in 2009, which was significantly higher than that in the herbicide treatment. We suggest that the initial release average density of O. communa adults should be ≥1.07 beetles per plant at the early growth stage, or ≥12 beetles per plant at the late growth stage for an effective control of A. artemisiifolia in the field.     

Host specificity of Argopistes tsekooni (Coleoptera: Chrysomelidae), a potential biological control agent of Chinese privet

Chinese privet, Ligustrum sinense Lour., is a perennial semi-evergreen shrub that is a serious invasive weed in the United States. Classical biological control offers the best hope for controlling it in an economic, effective, and persistent way. Host specificity of one of the most promising biological control agents of Chinese privet, a flea beetle, Argopistes tsekooni Chen (Coleoptera: Chrysomelidae), was evaluated in China by using laboratory no-choice and choice tests on 13 species of Oleaceae and eight species in other families that have important economic value. In adult no-choice survival and oviposition tests, the flea beetle fed and survived for 30 d on Syringa oblata Lindl., Jasminum nudiflorum Lindl., and three species in the genus Ligustrum. Females also oviposited on these species, but only larvae from eggs laid on S. oblata and Ligustrum spp. developed successfully. In addition, the beetles did not feed or oviposit on the species of economic importance. In choice tests, adults preferred L. sinense for feeding and oviposition. These results show that A. tsekooni is relatively host specific and warrants further testing as a biocontrol agent of Chinese privet in the United States.